STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
is particularly useful when using the jammed-bit-8 zero code suppression in
the transmit direction, for instance when sending a Nx56kbps fractional T1/E1
loopback sequence. This bit has no effect when UNF_GEN is set to logic 1.
Nx56k_DET:
The Nx56k_DET bit is active when the RPSC or TPSC is used to detect
PRBS in selected DS0 channels of the transmit or receive stream. When the
Nx56kbps detection bit is set to logic 1, the pattern generator only looks at
the first 7 bits of the selected DS0 channels, and gaps out the eighth bit. This
is particularly useful when searching for fractional T1 loopback codes in an
Nx56kbps fractional T1 signal. This bit has no effect when UNF_DET is set
to logic 1.
RXPATGEN:
The Receive Pattern Generate (RXPATGEN) bit controls the location of the
pattern generator/detector. When RXPATGEN is set to logic 1, the pattern
generator is inserted in the receive path and the pattern detector is inserted in
the transmit path. Timeslots from the receive line may be overwritten with
generated patterns before appearing on the receive backplane interface, and
timeslots from the transmit backplane interface may be checked for the
generated pattern before appearing on the transmit line. When RXPATGEN
is set to logic 0, the pattern detector is inserted in the receive path and the
pattern generator is inserted in the transmit path. Timeslots from the transmit
backplane interface may be overwritten with generated patterns before
appearing on the transmit line, and timeslots from the receive line may be
checked for the generated pattern before appearing on the receive backplane
interface.
UNF_GEN
When the Unframed Pattern Generation bit (UNF_GEN) is set to logic 1, the
PRGD will overwrite all 193 bits/256 bits in every frame in the direction
specified by the RXPATGEN bit. If the generator is enabled in the transmit
path, unless signaling and/or framing is disabled, the transmitter will still
overwrite the signaling bit positions and/or the framing bit position. Similarly,
if pattern generation is enabled in the receive direction, the pattern will
overwrite the framing bit positions. The UNF_GEN bit overrides any per-
timeslot pattern generation specified in the TPSC or RPSC. When
RXPATGEN = 0, UNF_GEN also overrides idle code insertion and data
inversion in the transmit direction, just like the TEST bit in the TPSC.
UNF_DET
When the Unframed Pattern Detection bit (UNF_DET) is set to logic 1, the
PRGD will search for the pattern in all 193 bits/256 bits of the transmit or
PROPRIETARY AND CONFIDENTIAL
106
PMC [ PMC-SIERRA, INC ]
